The invention relates to a test set for a photometric measuring device, including a mixing container which has a filling opening, and a dosing container which can be inserted in a sealing manner into the filling opening of the mixing container and which contains a liquid reagent in a closed cavity, wherein the cavity includes a closing plunger at a first end of the dosing container which can be moved axially in the cavity, the closing plunger generating a predeterminable filling pressure in the reagent, and the dosing container includes a closure membrane at a second end of the dosing container which can be inserted into the mixing container. The invention further relates to a photometric measuring method for a sample liquid.